Thanks for point 1. (Currently looking into points 2 and 3)
The content area most used on the site is 810px wide so I started off with changing
$CKEditor_config["width"] = "98%"; to $CKEditor_config["width"] = "810px";
This was far too wide for the editor content area so gradually reduced it to get to 574px which gave the same effective editor window width as the site div width.
Now its much easier to see the position of the line breaks etc on the editor window as they match the position of the line breaks on the site.
This is much easier for the client to use.